1. Field of the Invention
The present invention relates to a method and apparatus for loading and unloading containers onto and off of the rear bed of a truck without requiring the driver to dismount from the cab.
2. Description of the Prior Art
The present state of hauling loads via trucks has developed to the point where containers, which are preloaded at a site, are displaceably mounted on the rear bed of a truck for transport. This technique has many advantages, most of which are economic, in that the truck is not tied up during loading of the container and the number of people involved in the loading operation can be reduced. The principles involved in this type of hauling apply equally to raw materials, finished goods and refuse.
Tractor trailer combinations are an example of the type of vehicle designed for the above concept. It is quite evident from the highways that this form of trucking is in wide use. However, the tractor trailer or "semi" does not satisfy all hauling conditions. For example, trash is commonly collected in large containers kept at fixed locations and periodically unloaded into containers fixed to a truck. The trucks currently available for this type of work have several drawbacks, including the requirement for help, in addition to the driver, and the inevitable spillage on site. Also, these trucks are limited as to the size container they can handle and/or the operating equipment as potential safety hazards, such as free falling containers during unloading. Most of the available trucks simply release the container and allow gravity to do the unloading, with the truck pulling out from under the partially unloaded container. This naturally causes a great deal of unnecessary noise and, in the case of finished product, could cause damage to the items being transported. Further, since the prior trucks have used gravity as the unloading force, it is substantially impossible to unload the container onto a dock or trailer which is at the same height as the bed of the truck. Likewise, the trucks to date have not been capable of loading a container from a dock, trailer or the like, which is at the height of the truck bed.
Examples of the prior trucks and loading assemblies can be found in U.S. Pat. Nos. 3,077,278; 3,144,149; 3,857,504; 3,894,644 and 4,165,007.